During a botched execution of inmate Clayton Lockett in Oklahoma, a mystery lethal drug cocktail was injected from veins in his groin.

During a botched execution of inmate Clayton Lockett in Oklahoma, a mystery lethal drug cocktail was injected from veins in his groin after a phlebotomist was unable to find suitable entry in his extremities or neck.

They took 51 minutes to find a suitable vein and did not realize the one they ultimately found in his groin had collapsed, various sources have reported.

Clayton Lockett succumbed to a complication that ensued as a result of the lethal injection and died of a massive heart attack 10 minutes later, as he writhed and mumbled.

A timeline into the inmate's execution process released by the state's Corrections Department on Thursday also revealed that the convicted murderer and rapist had a self-inflicted wound on his arm and that he had refused to eat or see his attorney during the final hours leading up to the execution, NewsOk reported.

Before the execution on Tuesday, Lockett was also shocked with a taser after refusing to undergo an x-ray that is given to all convicted prisoners.

After the injection was pumped into the inmate's groin, his lower body was covered with a sheet, according to prisons director Robert Patton's letter to Oklahoma Governor Mary Fallin, which included a detailed timeline.

Soon after the legal injection; Lockett began writhing, clenching his teeth and straining to lift his head at a time he was supposed to be unconscious. This effect is thought to have been caused by the first of three drugs in the state's new lethal injection combination administered to the inmate.

The murderer's family has spoken out saying Lockett deserved to pay for his crimes, but no to suffer.

"I'm not seeking financial gain from this," Lockett's stepmother told NBC. "My main thing is I want the process changed...I want them to admit they did wrong and after that, let's change this...If we are going to put people to death, let's do it the right way."